Troubleshooting
Combi Boiler Pressure Too High
When the gauge climbs into the red.
If your boiler pressure climbs above roughly 2.5–3 bar, especially when heating, the pressure relief valve may discharge water outside. Persistent high pressure stresses the system and usually points to an overfilled system, a passing filling loop, or a failed expansion vessel.
Diagnosis involves the sealed system and expansion vessel, so it's best handled by a technician.
Common causes
- Filling loop left open or passing water
- Failed or under-charged expansion vessel
- Faulty pressure relief valve
- System overfilled during top-up
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
Call 778-909-5731Related symptoms & help
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